IT201900009198A1 - COMPACTION APPARATUS OF A CONTINUOUS TEXTILE SUBSTRATE THROUGH ELASTIC TAPE - Google Patents

Description

DESCRIPTION

Field of application

The object of the present invention is an apparatus for compacting a continuous textile substrate by means of an elastic belt.

State of the art

As is known, the process of compacting fabrics or textile substrates is one of the main processes in the field of textile finishing and has the purpose of imparting stability to the fabrics before moving on to the manufacturing phase.

Usually the stability and compaction to the fabric is impressed with machines with consolidated technology that exploit a change of curvature of a felt or rubber belt on which the fabric is placed on which to apply the compaction. The change of curvature of the support (felt or rubber tape) then gives the fabric a longitudinal indentation which is then pressed against a hot cylinder, which stabilizes the compacting effect, ensuring the dimensional stability of the fabric once it has been released from the machine.

All fabrics (be they orthogonal or knitted), after being produced, require a stabilization and compaction process that makes them suitable to be then cut for packaging. The compacting machines are therefore used extensively in the finishing processes. The obtainable compaction values depend on the initial stability degree of the fabric produced. The degree of initial stability of a fabric in turn depends on the type of material it is made of.

Frequently, it is necessary to carry out several passages of the same fabric through compacting machines in order to obtain the desired compaction result. This is particularly the case if the tissue originally had a high degree of instability. All this lengthens treatment times and affects production costs.

The need to reduce the times of the fabric compaction processes is therefore very much felt in the sector, especially in the case of fabrics (for example made of viscose) that are characterized by high degrees of initial instability.

Over time, different alternative technical solutions have been proposed, which aimed at making compaction systems more efficient. However, these solutions proved not to be completely satisfactory. More specifically, the compacting (or shrinking) treatment of fabrics is essentially carried out using a so-called "compression" technique which is based on the use of a substantially deformable belt, to which the fabric to be compacted is tightly coupled. The deformation of the strip in the longitudinal direction of advancement, by mechanical means suitable for the purpose, is substantially constituted by the succession of a first expansion step and a second contraction step. The fabric, integrally engaged to the deformable surface of the belt, undergoes, in particular during the contraction phase, a "compression" in the direction of advancement, or a compaction of its structure and, ultimately, a longitudinal shrinkage.

The deformability of the strip can be determined by the type and characteristics of the material of which it is made and also by the type of mechanical stress exerted on it by the mechanical means suitable for deforming it. Thus, deformations due to crushing of the belt are known which cause an expansion (elongation) followed by a contraction (shortening) in the initial relaxed state; or deformations due to variation of the peripheral speed of the strip obtained by making it slide on rollers or cylinders with different radius of curvature with an alternately convex and concave path which alternatively cause an increase (elongation) and a decrease (shortening) of the peripheral speed; or, finally, strains due to longitudinal traction of the belt (elongation) followed by a release of traction (shortening) in the initial relaxed state. Patent GB 563 638 describes an apparatus for compacting fabrics which aims to improve the known technique by using an endless elastic belt supported and guided by rollers, one of which rotates at a variable speed and higher than the roller. that precedes it. In this way, the portion of the belt comprised between said two rollers is placed in a state of elongation, while in the next section, when the tension is relaxed, the belt undergoes a longitudinal contraction of an amount equal to the previous elongation. The fabric, coupled to the belt at its elongated portion, follows it in the subsequent relaxed portion, partially wrapping around a rotating and heated cylinder, also undergoing a corresponding longitudinal contraction or shrinkage.

This technique, however, is not free from drawbacks, the first of which relates to the fact that the elastic band is made to rotate between the guide rollers in a completely and naturally relaxed state. Consequently, in the stretch of tension release, subsequent to that in which the longitudinal traction is applied which causes its elongation, the belt completely returns to its naturally relaxed state, without maintaining any minimum residual tension that allows it to transport and effectively guiding the fabric during the shrinking phase and not even offering any control of its own path around its guide rollers.

A further negative aspect is linked to the fact that the elastic band, therefore extensible in length, subjected to longitudinal traction also deforms transversely with a consequent and uncontrollable decrease in width. When the tensile stress ceases, both dimensions of the belt tend to regain their original measurements, that is to say that it widens again and since, as mentioned, it has not maintained any minimum residual tension, its surface tends to slide loosely and not stretched. transmitting these irregularities to the fabric coupled to it.

The technical solution proposed in the European patent application EP1657340A1 overcomes the drawbacks described above.

In more detail, this solution provides for a pre-tensioning traction to be applied to the elastic band so that it maintains a minimum residual tension at the end of the traction release phase that caused its elongation.

More in detail, the tissue compacting apparatus described in EP1657340A1 comprises a heated rotating cylinder around which an elastic tape is partially wrapped. The elastic belt is moved by means of a plurality of motorized rollers and idle return rollers according to a predefined closed path.

The roller apparatus is configured in such a way that by operating on the relative position of one of the idle rollers it is possible - when assembling the belt on the rollers - to pre-tension the belt itself with respect to its relaxed state. During the operation of the apparatus, compared to this basic state of pre-tensioning, the elastic band is further tensioned by elongation before coming into contact with the cylinder. When the web comes into contact with the fabric in the winding section around the cylinder, the web is free to contract longitudinally, dragging the fabric with it in a relative movement with respect to the cylinder. In this way, the fabric is dragged by the longitudinal contraction movement of the elastic band and is thus compacted longitudinally.

The compaction apparatus described above allows to improve the compaction process thanks to the pretensioning of the belt, but the results obtained are however not completely satisfactory.

The owner of the present patent application has been able to note, in particular, that the compacting of the textile substrate is disturbed by tensions induced on the web in a non-homogeneous way by the direct contact between the web and the heated cylinder.

More in detail, in the compacting apparatuses the contact area (direct or indirect) between the hot roll and the elastic strip is a highly unstable area as it meets the elastic deformability characteristics of the strip with the rigidity of the surface of the hot roll in steel.

As already highlighted, in this area of the compacting apparatus, the elastic belt exerts its compacting action on the textile substrate by transmitting to the substrate its own movement of contraction and return to the original length (pre-tensioned). In this area of the apparatus, the elastic tape slides on the surface of the hot cylinder since the tape and the hot cylinder, while moving in the same direction, can never have identical speeds. It should in fact be noted that the shortening effect of the elastic tape due to the relaxation of the tension generates an apparent negative speed resulting in a slowing effect of the tape with respect to the hot cylinder.

To this effect is added the slowing down of the belt caused by the friction generated by the direct contact between the belt and the cylinder.

More in detail, the heated cylinder and the elastic band are sized in such a way that their height is greater than the heights of the textile substrates which are normally subjected to compaction. Therefore, during use it is inevitable that the elastic tape comes into direct contact with the heated cylinder in correspondence with two bands located laterally to the textile substrate that runs between the elastic tape and the cylinder.

In correspondence of these two lateral bands, due to the high coefficient of friction between the material of the elastic band and the metal of the cylinder, sliding and friction occur which oppose the relaxation of the band, locally raising the temperature. This braking effect localized on the side bands also tends to deform the band in a different way with respect to the central band in which, instead, the elastic band does not come into direct contact with the side surface of the heated cylinder due to the presence of the textile substrate being treated. In fact, in the central band it is the latter that slides directly on the cylinder thanks to a low coefficient of friction.

These localized deformations create tension on the entire belt and disturb its shrinkage. This negatively affects the compaction of the textile substrate being treated, which therefore loses its efficiency.

Furthermore, the non-homogeneous sliding of the belt generates waves along the length of the belt itself. These waves, in addition to mechanically stress the belt, reducing its useful operating life, are transmitted to the textile substrate being treated, causing unwanted creases and tensions in it.

Finally, over time the thermal stresses caused by rubbing and friction contribute to premature wear of the elastic band, with a consequent reduction in its useful operating life.

The owner of this patent application has therefore found that the phenomena described above negatively affect the efficiency of the compaction process.

The present invention therefore aims to address the problems related to these phenomena, meeting a general need present in the sector, that is, to make the compacting of the textile substrate more efficient, possibly also increasing the operational useful life of the elastic tape.

Presentation of the invention

Therefore, the object of the present invention is to eliminate in whole or in part the drawbacks of the aforementioned prior art, by providing an apparatus for compacting textile substrates by means of an elastic belt which allows to make the compacting of the textile substrate more efficient and to increase the operational useful life of the elastic tape.

A further object of the present invention is to provide an apparatus for compacting fabrics by means of an elastic belt which allows to reduce the stresses imposed on the elastic belt during the contraction phase in contact with the heatable cylinder.

A further object of the present invention is to provide an apparatus for compacting fabrics by means of an elastic belt which is simple and economical to manufacture.

A further object of the present invention is to provide an apparatus for compacting fabrics by means of an elastic belt which can be operated in an operationally simple way.

Brief description of the drawings

The technical characteristics of the invention, according to the aforementioned purposes, are clearly verifiable from the content of the claims reported below and the advantages thereof will become more evident in the detailed description that follows, made with reference to the attached drawings, which represent one or more forms of purely illustrative and non-limiting realization, in which:

Figure 1 shows a side schematic view of an apparatus for compacting textile substrates by means of an elastic belt according to a first embodiment of the present invention;

Figure 2 shows an enlarged view of a detail of the diagram of Figure 1 relating to the compacting zone of the textile substrate, in which the elastic band partially wraps the heated cylinder; - Figure 3 shows a perspective view from above of the portion of the compaction apparatus illustrated in Figure 2;

- Figure 4 shows a lateral orthogonal view of the portion of the compaction apparatus illustrated in Figure 2 according to the arrow IV shown therein;

Figure 5 shows a side schematic view of an apparatus for compacting textile substrates by means of an elastic belt according to an alternative embodiment of the present invention;

Figure 6 shows an enlarged view of a detail of the diagram of Figure 5 relating to the compacting zone of the textile substrate, in which the elastic band partially wraps the heated cylinder;

- Figure 7 shows a perspective view from above of the portion of the compaction apparatus illustrated in Figure 6;

- Figure 8 shows a lateral orthogonal view of the portion of the compaction apparatus illustrated in Figure 6 according to the arrow VIII shown therein.

Detailed description

With reference to the accompanying drawings, the number 1 indicates as a whole a compacting apparatus for a continuous textile substrate by means of an elastic belt according to the invention.

Advantageously, the textile substrate T can be of any type; in particular it can be an orthogonal (shuttle) fabric or a knitted fabric. The textile substrate can be formed from any type of fiber used for woven and knitted fabrics.

As shown schematically in Figures 1 and 4, the compaction apparatus 1 includes:

- a heatable rotating cylinder 10;

- an endless belt 20 which is elastically deformable in elongation and can be moved along a closed path to support and transport a textile substrate T in contact with a lateral surface portion 10a of said heatable rotating cylinder 10;

- a system of rollers 31, 32, 33, 34, 35 on which the tape 20 is wound in a state of pre-tension in elongation.

In turn, this roller system comprises a plurality of idle return rollers 33, 34, 35 and a plurality of motorized rollers 31, 32.

The motorized rollers 31, 32 can be actuated in such a way as to make the belt 20 slide along the aforementioned closed path, imposing on the belt a tensional state of additional elongation with respect to the pre-tensioning state in correspondence with a first section T1 of said path which extends - with respect to to a direction of advancement X of the belt - upstream of a second section T2 of this path in which said belt 20 is kept in contact with the rotating cylinder.

The compacting apparatus 1 also comprises means 40 for guiding a textile substrate T between the belt 20 and the heatable cylinder 10 along the second section T2) of this closed path.

Operationally, the compacting action on the textile substrate T occurs along the aforementioned second stretch T2 of the closed path. In correspondence with this second portion T2, the elastic band contracts elastically, passing from the additional tensional state of elongation, which was imposed on it upstream in the first portion T1, to a state close to that of pre-tensioning. The textile substrate T, which in the second section T2 moves solidly with the belt 20 thanks to the friction forces, undergoes the contraction of the belt itself, and in turn contracts in a longitudinal direction, compacting itself.

As shown in the attached Figures, the compacting apparatus 1 comprises a system for reducing the coefficient of friction between the belt 20 and the heatable rotating cylinder 10.

This friction reduction system in turn comprises one or more interposition bands 61, 62 or 63 which are guided in partial winding around the cylinder 10 and in direct contact with its lateral surface 10a to interpose between the belt 20 and the lateral surface 10a of the cylinder 10 along the aforementioned second portion T2 of the closed path of the belt.

The interposition between the strip and the cylinder of such one or more interposition bands 61, 62 or 63 occurs at least in correspondence with two axial end bands 11, 12 of the lateral surface 10a of the cylinder 10 which are in axially opposite positions with respect to the 'Y axis of rotation of the cylinder itself.

Said one or more interposition bands 61, 62 or 63 are made of a material which is able to generate with the lateral surface of the cylinder 10 a lower friction coefficient than that generated with the belt 20. Operationally, the reduction system of the friction coefficient therefore intervenes at least in correspondence with the two axial end bands of the lateral surface 10a of the cylinder 10 which in use are generally left uncovered by the textile substrate T being treated.

In other words, the friction coefficient reduction system is configured to avoid direct contact between the elastic band 20 and the side surface 10a of the cylinder 10.

Operationally, the invention exploits the physical phenomena related to the friction between different materials: elastic tape material; material of the interposition bands; metal of the heatable cylinder.

Frictional forces are generated between the elastic tape and the textile material that are higher than those generated between the textile material and the metal surface of the heatable cylinder.

Preferably, the interposition bands are made of a material that generates the lowest possible frictional forces with the metal surface of the cylinder.

It follows that the aforementioned one or more interposition bands tend to move integrally with the elastic band and to follow its contraction movements, while said one or more bands tend to slide freely on the metal surface of the cylinder. The interposition bands therefore act as a kind of solid lubricant.

In this way, in correspondence with the aforementioned axial end bands of the cylinder - thanks to the interposition of said one or more bands between the belt and the cylinder - operating conditions similar to those in use in the central band occupied by the textile substrate are substantially recreated. T in treatment, which is interposed between the belt and the cylinder. This creates a homogeneous system for reducing friction between the belt and the cylinder, with beneficial effects in terms of:

- reduction of the heat generated on the elastic band;

- reduction of mechanical stresses on the elastic band generated by localized tensions due to different sliding speeds on the cylinder of the different portions of the band itself;

- reduction of the disturbance phenomena of the contraction / withdrawal movements of the elastic band.

Consequently, thanks to the invention we have:

- increase in the operational useful life of the elastic band; And

- greater efficiency of the compaction process.

A further advantage with respect to prior art solutions lies in the fact that the heatable cylinder 10 will no longer require particular and expensive surface treatments designed to reduce the coefficient of friction with the belt 20, but a normal surface treatment will suffice to obtain a roughness compatible with the material of the interposition bands to obtain reduced coefficients of friction. This can be achieved with low cost surface coatings, obtained for example by nitriding, chrome plating, deep / hard chrome plating.

Preferably, the lateral surface 10a of the cylinder 10 has a roughness Ra of between 10 microns and 40 microns. In other words, unlike the solutions of the known art, the roughness of the lateral surface 10a of the cylinder 10 is no longer a fundamental parameter, since a direct contact between the belt 10 and the cylinder 20 is no longer provided.

Advantageously, thanks to the fact that said one or more interposition bands slide without friction on the lateral surface of the cylinder, remaining integral with the elastic band, they are not substantially subject to either significant sliding phenomena or significant overheating phenomena. The operational useful life of these bands is therefore high. This results in reduced operational maintenance requirements.

Preferably, said one or more interposition bands 61, 62 or 63 are made of fabric or non-woven fabric.

In this way, the interposition bands have mechanical characteristics comparable to those of the textile substrates T which are treated by the compacting apparatus 1.

In particular, the choice of a fabric or a non-woven fabric makes the interposition bands more capable of following the contraction movements of the tape 20, thanks to intrinsic properties of deformability. The risk that the interposition bands may disturb the movements of the tape 20 is therefore reduced.

According to a first embodiment, said one or more interposition bands can be made of a fabric of natural textile fibers, preferably selected from the group consisting of cotton, wool, cellulose. According to an alternative embodiment, said one or more interposition bands are made of a fabric or a non-woven fabric made of synthetic fibers, preferably selected from the group consisting of polyester and nylon.

Said one or more interposition bands can be made of a mixed fabric of natural fibers and synthetic fibers.

According to a particularly preferred embodiment, the aforementioned fabric or non-woven fabric comprises elastomeric fibers. Preferably, the aforementioned one or more interposition bands are made of a fabric defined by a blend of polyester-elastane and / or nylon-elastane fibers.

Preferably, said fabric or said non-woven fabric has a grammage of not less than 50g / m2. It has in fact been found that there are improved effects in terms of increased compaction efficiency compared to the case of using fabrics or non-woven fabrics with weights of less than 50 g / m2.

In accordance with an embodiment not shown in the attached drawings, the compacting apparatus 1 comprises means for wetting with an aqueous solution, preferably only water, called one or more interposition bands 61, 62 or 63.

Preferably, the wetting of the interposition bands is provided in the event that these bands are made of fabric or non-woven fabric. It has been found that the wetting of the bands facilitates their sliding on the surface of the cylinder and has beneficial effects on the compacting process of the textile substrate T to be treated.

In accordance with a preferred embodiment, illustrated in Figures 5 to 8, the aforementioned friction coefficient reduction system includes two distinct interposition bands 61, 62.

As can be observed in particular in Figures 7 and 8, these two distinct bands 61 and 62 are guided in partial winding around the cylinder 10 and in direct contact with its lateral surface to interpose between the strip 20 and the lateral surface 10a of the cylinder 10 along the aforementioned second portion T2 of the closed path of the belt.

More in detail, a first interposition band 61 is guided at a first axial end band 11 of the lateral surface 10a of the cylinder 10 and a second interposition band 62 is guided at a second axial end band 12 of the lateral surface 10a of the cylinder 10.

These two interposition bands 61, 62 leave a central band 13 of the lateral surface 10a of the cylinder 10 uncovered to allow in use to a textile substrate T to be treated to slide in direct contact with the cylinder 10.

Preferably, the axial winding position of both or at least one of said two interposition bands 61, 62 around the cylinder 10 is adjustable so as to vary the width in the axial direction (height) of the uncovered central band 13. This adjustment of the axial position is made according to the height H of the textile substrate T to be treated.

Preferably, since the compacting apparatus 1 can be called upon to treat textile substrates T having different heights H, during the design phase the interposition bands are sized in terms of height H1 and H2 with the maximum value that can be assumed as a function of the height minimum Hmin that the textile substrate can have.

More in detail, the two bands 61 and 62 must have a total height H1 H2 as a whole such as to cover the two end bands 11 and 12, in the event that the apparatus 1 treats a textile substrate with a minimum height Hmin. In other words, if the axial development of the strip 10 is equal to Hn (it could be equal to or less than the axial development of the cylinder Hc), (H1 H2 Hmin) must be equal to or greater than Hn.

In other words, the heights H1 and H2 of the two bands 61 and 62 must be sized in such a way that the two end bands 11 and 12 left uncovered by the textile substrate T can always be covered by the two interposition bands 61 and 62.

Operationally, it is allowed that the interposition bands 61 and 62 may overhang axially with respect to the tape 20 or the cylinder 10.

According to an alternative embodiment, illustrated in Figures 1 to 4, the aforementioned friction coefficient reduction system can comprise a single interposition band 63 which is partially wound around the cylinder 10 and in direct contact with its lateral surface 10a to be interposed between the belt 20 and the lateral surface of the cylinder 10 along said second portion T2 of the closed path of the belt.

As can be observed in particular in Figures 3 and 4, said single interposition band 63 has an axial extension H3 at least equal to the axial extension Hn of said tape 20.

In use, said single interposition band 63 is therefore also interposed between the textile substrate T to be treated and the lateral surface 10a of the cylinder 10.

In this case, the textile substrate T to be treated does not come into contact with the cylinder 10, but with the interposition band 63.

Thanks to the friction that forms between the textile substrate T and the interposition band 63 (in particular when it is made of fabric or non-woven fabric), the interposition band 63 will tend to follow integrally the textile substrate T and to slide freely with respect to the surface of the cylinder 10. There will therefore be no slipping between the textile substrate T and the interposition band 63. The textile substrate T will therefore not be disturbed by the interposition band and can therefore follow the contraction movements of the belt 20, for the benefit of a correct performance of the compaction process.

Compared to the case of two distinct interposition bands 61 and 62, the use of a single band 63 avoids the need to adjust the winding position around cylinder 10.

However, the embodiment with two distinct bands 61 and 62 adjustable in position is preferred since in this way the tape 20 substantially does not encounter thickness discontinuities in its winding around the cylinder 10. Otherwise, in the case of a single band 63, in correspondence of the lateral edges of the textile substrate T, the tape 20 encounters a reduction in thickness, which could disturb it.

Advantageously, as illustrated in the attached Figures, each of said one or more interposition bands 61, 62 and 63 forms an endless belt which is wound around the cylinder 10 and a guide system comprising one or more return rollers 71, 72.

Preferably, the two distinct interposition bands 61, 62 are both guided by the same guide system.

Advantageously, the friction reduction system described above is applicable in any compacting apparatus with elastic belt, which provides for the pre-tensioning of the belt itself.

Preferably, as illustrated in the attached Figures, the friction reduction system according to the invention is applied on a compaction apparatus as described below.

The aforementioned system of rollers, on which the tape 20 is wound in a state of pre-tension in elongation, comprises:

- a motorized drawing roller 31;

- a motorized brake roller 32;

- a first idle return roller 33, which is arranged between the motorized brake roller 31 and the motorized brake roller 32; and

- a second idle return roller 34.

With reference to the direction of advancement X of the belt 20 along the closed path, the motorized drive roller 31 is the roller immediately upstream of the heatable cylinder 10, while the second idle return roller 34 is the roller immediately downstream of the cylinder heatable 10.

The first portion T1 of the aforementioned closed path (in correspondence with which in use the belt 20 is elastically elongated receiving a tensional state of additional elongation with respect to the pre-tensioning one) extends between the motorized brake roller 32 and the motorized drive roller 31 , passing in partial winding around the first idle return roller 33.

The second stretch of path T2 (in correspondence with which the belt 20 contracts in use, losing the tensional state of additional elongation to return to the pre-tensioned state) extends between the motorized drive roller 31 and the second idle return roller 34.

The aforementioned closed path is completed by a third path section T3 which extends between the second idle return roller 34 and the motorized brake roller 32. In use, along this third path section T3, the belt 20 is located in one relaxed stress state with respect to the first stretch of path T1, substantially corresponding to the pre-tensioned state.

The “closed path” corresponds to the total development of the belt 20 when mounted in pre-tension on the roller system. The closed path is not affected by local stretching and contractions of the tape.

Thanks to this particular configuration of the roller system, in the closed path there is a section of path - distinct from that of contraction in contact with the cylinder - in which the belt is free to gradually return to the pre-tensioned state, without being subjected to a state of additional elongation.

On the other hand, in the solutions of the known art which provide for the pre-tensioning of the belt, but with a different configuration of the roller system, referring to the tensional state of the belt, the closed path of the belt is divided into only two sections:

- a first "elongation" section, which extends from a brake roller arranged immediately downstream of the heatable cylinder to a tow roller arranged immediately downstream of the heatable cylinder; and - a second "contraction" section which extends from the drive roller to the brake roller, partially wrapping the heatable cylinder.

According to the known art, the tape is therefore continuously stressed in elongation or contraction, without actually being able to remain in the state of pre-tension, that is, in the state of minimum elongation, which can be considered the state of rest. In fact, already immediately downstream of the brake roller, the belt begins to undergo the elongation action exerted by the tow roller.

Otherwise, thanks to the aforementioned configuration of the roller system, the aforementioned third portion T3 has been inserted into the closed path, in which the belt - after having contracted in the second portion T2 - is free to remain in the pre-tensioned state. In other words, the third stretch T3 can be considered a rest stretch for the belt, as opposed to the first stretch T1 and the second contraction stretch T2. This has a number of advantages:

- the tensile elongation action exerted on the belt is concentrated on a shorter section of the path (with the same extension of the closed path and the second section T2); in this way, by acting on the speeds of the motorized towing and brake rollers, it is possible to control the elongation imposed on the belt more precisely, resulting in better control over the compacting action of the textile substrate;

- the belt is less mechanically stressed, since, after having contracted, it is free to reach the rest state and remain there for a certain distance; the reduction of the stresses on the belt allows to extend the useful life of the belt itself.

These advantages are enhanced by the adoption of the friction reduction system according to the present invention. Preferably, the motorized drive rollers 31 and brake 32, the idle return rollers 33, 34, 35, as well as the heatable cylinder 10 are made of metal, preferably of steel.

In accordance with a particularly preferred embodiment of the invention, as illustrated in the attached Figures, the motorized brake roller 32 and the motorized tow roller 31 are both equipped with a rubber coating 36 which covers the respective cylindrical lateral surfaces intended to be in contact with the tape 20.

Thanks to the rubber coating 36 of the motorized rollers, the friction coefficient between motorized rollers and the belt is increased compared to the case of contact of the belt on the bare surface of the cylinder, typically smooth metal.

Operationally, the increase in the friction coefficient reduces the risk of slipping between the belt and rollers. This helps to improve the control over the elongation action of the belt and therefore to increase the efficiency of the compacting process of the textile substrate.

Preferably, both the first idle return roller 33 and the second idle return roller 34, unlike the two motorized rollers 31 and 32, are not rubber-coated. In other words, both the first idle return roller 33 and the second idle return roller 34 are equipped with a cylindrical lateral surface, preferably made of metallic material, intended to come into direct contact with the belt 20 without the interposition of a rubber coating covering this cylindrical lateral surface.

Operationally, thanks to the fact that the idle return rollers 33 and 34 are not rubberized and the elastic belt 20 comes into direct contact with their metal side surface, the friction between the belt and idle rollers is reduced. In this way, thanks to the reduction of friction, the belt encounters fewer obstacles in its elastic extension and in its subsequent contraction.

Operationally, the tensional state of additional elongation is imposed on the belt 20 by acting on the speeds of the motorized drive roller 31 and of the motorized brake roller 32, so as to create a difference between the tangential speeds of the lateral surfaces of the two rollers (intended to enter in contact with the tape). The tensional state of elongation (measurable for example as a percentage of elongation with respect to the pre-tensioned state) increases as the difference in these speeds increases.

Advantageously, the apparatus 1 can comprise a control unit 50, preferably electronic, configured to control the rotation of the motorized drive roller 31 and of the motorized brake roller 32 so that said two motorized rollers 31, 32 rotate in the same towards and in such a way that the tangential speed Vt of the motorized drawing roller 31 is higher than the tangential speed Vf of the motorized brake roller 31 according to a predefined ratio Vf / Vt.

Advantageously, this predefined ratio Vf / Vt between the tangential speed of the motorized brake roller 32 and the tangential speed of said motorized towing roller 31 is adjustable according to the amount of additional longitudinal elongation to be imposed on the belt in correspondence with the first section of route T1.

Preferably, said predefined Vf / Vt ratio is comprised between 0.5 and 0.9, and preferably equal to 0.7.

Preferably, the heatable rotating cylinder 10 is motorized.

Advantageously, the control unit 50 is configured to control the rotation of the heatable cylinder in such a way that its tangential speed (referred to the lateral surface 10a) is as close as possible to the tangential speed of the motorized drive roller 31, and preferably equal to her.

It has been found that in these conditions the best results are obtained in terms of compacting the textile substrate. In other words, in these conditions the efficiency of the compaction process is increased.

Preferably, the motorized drive roller 31, the motorized brake roller 32 and the first idle return roller 33 are positioned together in such a way that the aforementioned first section T1 of the closed path has an extension in length not exceeding 35% of the length. entire path closed, and preferably not less than 10%.

Advantageously, as schematically illustrated in Figure 1, the motorized drive roller 31, the motorized brake roller 32 and the first idle return roller 33 are positioned relatively to each other so as to assume a compact configuration. By compact configuration we mean a configuration in which said three rollers 31, 32, and 33 are located in close positions to each other when compared with the other rollers 34 and 35 of the roller system.

The "compact configuration" is essentially aimed at reducing the extension of the first stretch T1 of the route as much as possible in favor of the third stretch T3 of the route.

In particular, said three rollers 31, 32, and 33 can be arranged to form a set of three rollers with aligned rotation centers. This choice is preferred from a constructive point of view since it allows a reduction of the overall dimensions and simplifies the support structure of the rollers themselves. However, configurations of the triad of rollers can be provided in which the rollers are not aligned with each other.

Preferably, the motorized drive roller 31, the motorized brake roller 32 and the first idle return roller 33 are positioned together in such a way that the angle of winding of said belt 20 around the motorized drive roller 31 and the roller motorized brake 32 is not less than 90 °.

In particular, as shown schematically in Figure 1, the belt is installed on the three rollers so as to follow an S-shaped path between the three rollers. In particular, the two motorized rollers 31 and 32 contact the belt on its internal surface, while the first idle return roller 33 contacts the belt on its external surface. The first idle return roller 33, interposed between the two motorized rollers 31 and 32, can thus push the belt against them, favoring the winding of the belt. The "thrust" action of the return roller and therefore the effect in terms of winding can be calibrated by operating on the nominal diameters of the rollers and / or on the relative position of the rotation centers.

Operationally, the higher the angle of wrapping of the tape on the drive roller 31 and on the brake roller 32, the greater the friction that is generated between the motorized rollers and the belt and therefore the more efficient the dragging action of the rollers. on the belt, with reduction of slippage phenomena between roller and belt.

All this contributes to improving the control over the elongation action of the belt and therefore to increasing the efficiency of the compacting process of the textile substrate.

As already highlighted above, with reference to the direction of advancement X of the belt 20 along the closed path, the motorized drive roller 31 is the roller placed immediately upstream of the heatable cylinder 10, while the second idle return roller 34 is the roller placed immediately downstream of the heatable cylinder 10.

Preferably, the motorized drive roller 31 and the second idle return roller 34 are positioned with respect to the cylinder 10 in such a way that:

- the distance D1 between the lateral surface 31a of the motorized drawing roller 31 and the lateral surface 10a of the cylinder 10 is equal to or less than the thickness S of the strip 20; and

- the distance D2 between the lateral surface 10a of the cylinder 10 and the lateral surface 34a of the second idle return roller 34 is equal to or greater than the thickness S of the strip 20.

Preferably, the aforementioned distance D1 is less than the thickness S of the strip 20 by a value comprised between about 0% and about 50%; the aforesaid distance D2 is greater than the thickness S of the strip 20 by a value between about 0% and about 100%.

Advantageously, the aforementioned second idle return roller 34 can be moved with respect to the other rollers 31, 32, 33 to vary their relative position and allow:

- assembly and disassembly of the belt on said roller system;

- belt maintenance operations; And

- the pretensioning of the belt 20.

In accordance with a particularly preferred embodiment, illustrated in Figure 1, the second idle return roller 34 can be moved with respect to the other rollers 31, 32, 33 along an arc of circumference concentric to the rotation axis of the cylinder 10 between a position of maximum wrapping of the tape around the cylinder and a position of minimum wrapping around the cylinder.

For this purpose, the second idle return roller 34 is slidingly engaged at both its axial ends to a guide (not shown in the attached Figures) shaped according to said arc of circumference.

Advantageously, the second idle return roller 34 can be locked both in the aforementioned two extreme positions of the aforementioned arc of circumference, and in one or more intermediate positions, so as to adjust the extension of said second section T2 of the closed path and therefore the degree for winding the ribbon around the cylinder 10. In this way it is possible to calibrate the compaction effect on the textile substrate according to the requirements dictated by the type of fiber and the result to be obtained. In this way, it is also possible to improve and decrease the friction effect of the tape on the hot cylinder due to the decrease in the wrapping angle. This has a benefit on the result of the compaction process.

The locking of the second idle return roller 34 along the aforementioned shaped guide can be achieved by means of brackets which also include bearings designed to rotate the roller pin and can be fixed, for example, by means of screws to the support structure of the apparatus. In particular, the roller is fixed in correspondence with suitably perforated shoulders along said guide in predefined angular positions corresponding to the adjustment positions that are to be made available.

Preferably, as shown in Figure 1, the arc of circumference has an extension of 90 °. Circumferential arcs of smaller or smaller amplitude can be provided according to operational requirements.

Adjusting the position of the second idle return roller 34 with respect to the cylinder 10 changes the state of tension of the belt.

Preferably, as illustrated in Figure 1, the apparatus 1 comprises a third idle return roller 34 which engages the belt in correspondence with the third section T3 of the path and can be moved with respect to the other rollers 31, 32, 33 to compensate for the variations in position of the second idle return roller 34.

Similarly to what is provided for the second idle return roller 34, also the third idle return roller 35 is slidingly engaged at both its axial ends to a suitably shaped guide (not shown in the attached Figures). The third idle roller 35 can also be fixed and stopped even in intermediate positions between two positions of maximum and minimum compensation. The fixing can be done by means of brackets that include the roller bearings and which will be fixed by screws behind the device suitably drilled at the predetermined positions.

Preferably, like the first and second idle return roller 33 and 34, the third idle return roller 35 is also not rubber-coated. In other words, the third idle return roller 35 is also equipped with a cylindrical lateral surface, preferably made of metallic material, intended to go into direct contact with the belt 20 without the interposition of a rubber coating to cover this surface. lateral cylindrical.

Operationally, as already highlighted in relation to the idle return rollers 33 and 34, also for the third idle return roll 35, thanks to the absence of gumming and therefore to the fact that the elastic band 20 comes into direct contact with the metal lateral surface of this third idle roller 35, the friction between the belt and the idle roller is reduced. In this way, thanks to the reduction of friction, the belt encounters fewer obstacles in its sliding, avoiding localized tension due to friction.

Preferably, the aforementioned belt 10 is elastically deformable in elongation for a percentage comprised between 5% and 100% of its length in the relaxed state before pre-tensioning and, preferably in its pre-tensioned state, for a percentage comprised between 30% and 50% of its relaxed length.

Preferably, the tape 20 has a thickness S comprised between about 4.0 mm and about 16.0 mm and, preferably, about 10 mm.

The tape 20 can be made of a substantially extensible and elastic material, in particular of natural or synthetic rubber, or combinations thereof. Advantageously, the material can contain additives suitable for improving its mechanical characteristics and heat resistance.

The invention allows to obtain numerous advantages already partially described.

The apparatus for compacting textile substrates using an elastic belt according to the invention makes it possible to make the compaction of the textile substrate more efficient and to increase the operational life of the elastic belt thanks to a reduction in friction between the belt and the cylinder.

The apparatus for compacting textile substrates using an elastic belt according to the invention allows to reduce the stresses imposed on the elastic belt during use, and in particular in the contraction area around the heatable cylinder.

The apparatus for compacting textile substrates by means of an elastic belt according to the invention is simple and inexpensive to make.

The apparatus for compacting textile substrates using an elastic belt according to the invention is manageable in an operationally simple way.

The apparatus for compacting textile substrates by means of elastic belt according to the invention allows in particular - thanks to a specific configuration of the roller system - to control more precisely the tensioning of the elastic belt so as to make the compacting process more efficient. fabrics. The apparatus for compacting textile substrates using an elastic belt according to the invention allows to reduce the stresses imposed on the elastic belt during use, as a whole and not only in correspondence with the contraction area.

Further advantages obtainable with the compaction apparatus according to the invention are listed below:

- High precision of belt elongation thanks to the use of rubberized rollers;

- Perfect towing guarantee without slipping of the belt on the tow and brake rollers thanks to the wide winding angle on the same (given by the idle roller interposed)

- High process speed, high productivity

- High compaction efficiency, high compaction value for all fabrics

- It does not require having to go over the same fabric several times in the apparatus to obtain a correct compaction value (process performed in a single step)

- Possibility of treating both orthogonal fabrics (shuttle) and knitted fabrics

- Possibility of treating all types of fibers used for woven and knitted fabrics

- Excellent compaction results at high speed even with viscose fiber fabrics

- Excellent compaction results at high speeds even with cotton fiber and jeans type fabrics Obviously, in its practical implementation, it can also assume shapes and configurations other than the one illustrated above without, for this reason, leaving the present scope of protection .

Furthermore, all the details can be replaced by technically equivalent elements and the dimensions, shapes and materials used can be any according to the needs.

Claims (27)

CLAIMS 1. Apparatus for compacting a continuous textile substrate (T) by means of an elastic belt, comprising: - a heatable rotating cylinder (10); - an endless belt (20) movable along a closed path (P) to support and transport the textile substrate (T) in contact with a lateral surface portion (11) of said heatable rotating cylinder (10), said belt being elastically deformable in elongation; - a system of rollers (31, 32, 33, 34, 35) on which said tape (20) is wound in an elongated pre-tensioned state, in which said roller system comprises a plurality of idle return rollers (33, 34, 35) and a plurality of motorized rollers (31, 32) which can be actuated so as to make said belt (20) slide along said closed path (PC), imposing on said belt an additional tension state of elongation in correspondence with a first section ( T1) of said path which extends - with respect to a direction of advancement (X) of the belt - upstream of a second portion (T2) of said path in which said belt (20) is kept in contact with the rotating cylinder; - means (40) for guiding said textile substrate (T) between said belt (20) and said heatable cylinder (10) along said second section (T2) of said path, characterized in that it comprises a system for reducing the coefficient of friction between the belt (20) and the heatable rotating cylinder (10), said friction reduction system comprising one or more interposition bands (61, 62; 63) which: - they are guided in partial winding around said cylinder (10) and in direct contact with its lateral surface (10a) to interpose between said belt (20) and the lateral surface (10a) of said cylinder (10) along said second section ( T2) of the closed path of the strip at least in correspondence with two axial end bands (11, 12) of the lateral surface of said cylinder (10) which are in axially opposite positions with respect to the rotation axis (Y) of the cylinder itself; And - they are made of a material that is able to generate with the lateral surface of the cylinder (10) a lower friction coefficient than that generated with the belt (20). 2. Apparatus according to claim 1, wherein said friction coefficient reduction system comprises two distinct interposition bands (61, 62) which are guided in partial winding around said cylinder (10) and in direct contact with its lateral surface to be interposed between said belt (20) and the lateral surface of said cylinder (10) along said second section (T2) of the closed path of the belt and in which a first interposition band (61) is guided at a first axial end band (11) of the side surface (10a) of said cylinder (10) and a second interposition band (62) is guided at a second axial end band (12) of the side surface (10a) of said cylinder (10), said two interposition bands (61, 62) leaving uncovered a central band (13) of the lateral surface (10a) of the cylinder (10) to allow in use a textile substrate (T) to be treated to scroll to contact or direct with the cylinder (10). 3. Apparatus according to claim 2, wherein the axial winding position of both or at least one of said interposition bands (61, 62) around said cylinder (10) is adjustable so as to vary the width in the direction axial (height) of said uncovered central band (13). 4. Apparatus according to claim 1, wherein said friction coefficient reduction system comprises a single interposition band (63) which is guided in partial winding around said cylinder (10) and in direct contact with its surface lateral to interpose between said belt (20) and the lateral surface of said cylinder (10) along said second section (T2) of the closed path of the belt and in which said single interposition band (63) has an axial extension (H3 ) at least equal to the axial extension (Hn) of the belt (20), in use said single interposition band (63) interposing itself between the textile substrate (T) to be treated and the lateral surface of said cylinder (10). 5. Apparatus according to one or more of the preceding claims in which each of said one or more interposition bands forms an endless belt which is wound around said cylinder and a guide system comprising one or more deviating rollers (71, 72). 6. Apparatus according to claim 2 or 3 and claim 5, in which said two distinct interposition bands (61, 62) are both guided by the same guide system. 7. Apparatus according to one or more of the preceding claims, in which said one or more interposition bands are made of fabric or non-woven fabric. 8. Apparatus according to one or more of the preceding claims, in which said one or more interposition bands are made of a fabric of natural textile fibers, preferably selected from the group consisting of cotton, wool, cellulose. 9. Apparatus according to one or more of the preceding claims, in which said one or more interposition bands are made of a fabric or a non-woven fabric made of synthetic fibers, preferably selected from the group consisting of polyester and nylon. 10. Apparatus according to one or more of the preceding claims, in which said one or more interposition bands are made of a mixed fabric of natural fibers and synthetic fibers. Apparatus according to any one of claims 7 to 10, wherein said fabric or said non-woven fabric comprises elastomeric fibers. 12. Apparatus according to one or more of claims 7 to 11, wherein said fabric or said non-woven fabric has a weight of not less than 50g / m2. Apparatus according to any one of the preceding claims, wherein said roller system comprises a motorized drive roller (31), a motorized brake roller (32), a first idle return roller (33), which is arranged between said motorized brake roller and said motorized brake roller, and a second idle return roller (34), and in which the first section (T1) of said path extends between said motorized brake roller (32) and said motorized tow roller (31), passing in partial winding around said first idle return roller (33), while said second section of path (T2) extends between said motorized drive roller (31) and said second idle return roller (34), in which said closed path is completed by a third section (T3) which extends between said second idle return roller (34) and said motorized brake roller (32), in use along said third path section (T3) said belt (20) being in a relaxed tension state with respect to the first path section (T1). Apparatus according to claim 13, wherein said motorized brake roller (32) and said motorized drive roller (31) are both provided with a rubber coating which covers the respective cylindrical lateral surfaces intended to come into contact with said belt (20). 15. Apparatus according to claim 14, wherein said first idle return roller (33) is equipped with a cylindrical lateral surface made of metallic material, intended to go into direct contact with said belt (20) without the interposition of a coating rubber to cover this cylindrical lateral surface. 16. Apparatus according to any one of claims 13, 14 and 15, wherein said second idle return roller (34) is equipped with a cylindrical lateral surface made of metallic material, intended to come into direct contact with said belt (20) without the interposition of a rubber coating to cover this cylindrical side surface. 17. Apparatus according to any one of claims 13 to 16, wherein said motorized drive roller (31), said motorized brake roller (32) and said first idle return roller (33) are positioned together in such a way that said first section (T1) of the closed path has an extension in length not greater than 35% of the entire closed path, and preferably not less than 10%. 18. Apparatus according to any one of claims 13 to 17, wherein said motorized drive roller (31), said motorized brake roller (32) and said first idle return roller (33) are positioned together in such a way that the winding angle of said tape (20) around said motorized drawing roller (31) and said motorized brake roller (32) is not less than 90 °. 19. Apparatus according to any one of claims 13 to 18, comprising a control unit (50) configured to control the rotation of said motorized drive roller (31) and said motorized brake roller (32) so that said two motorized rollers (31, 32) rotate in the same direction and in such a way that the tangential speed (Vt) of said motorized drawing roller (31) is higher than the tangential speed (Vf) of said motorized brake roller (31) according to a predefined ratio (Vf / Vt). 20. Apparatus according to claim 19, wherein said predefined ratio (Vf / Vt) between the tangential speed of said motorized brake roller (32) and the tangential speed of said motorized tow roller (31) is adjustable according to the amount of longitudinal elongation to be imposed on said belt in correspondence with said first section of path (T1). 21. Apparatus according to claim 20, wherein said predefined ratio (Vf / Vt) is comprised between 0.5 and 0.9, and preferably equal to 0.7. 22. Apparatus according to any one of the preceding claims, wherein said heatable cylinder (10) is motorized. 23. Apparatus according to any one of claims 19, 20 and 21 and claim 22, wherein said control unit (50) is configured to control the rotation of said heatable cylinder (10) such that its tangential velocity is referred to to its lateral surface (10a) - is as close as possible to the tangential speed of the motorized drawing roller (31), and preferably equal to it. 24. Apparatus according to any one of claims 13 to 23, in which said second idle return roller (34) can be moved with respect to the other rollers (31, 32, 33) to vary their relative position and allow the assembly and pre-tensioning of said belt (20) on said roller system. 25. Apparatus according to any one of claims 13 to 24, in which said second idle return roller (34) can be moved with respect to the other rollers (31, 32, 33) along an arc of circumference concentric to the rotation axis of the cylinder (10) between a position of maximum winding of the tape around said cylinder and a position of minimum winding around said cylinder and can be locked in one or more intermediate positions between said two positions to adjust the extension of said second section (T2) of the closed path and in which said apparatus (1) comprises a third idle return roller (34) which engages said belt in correspondence with said third section (T3) of the path and is movable with respect to the other rollers (31, 32, 33) to compensate variations in the position of said second idle return roller (34) and thus maintain the pre-tensioning of said belt. 26. Apparatus according to claim 25, wherein said third idle return roller (34) is equipped with a cylindrical lateral surface made of metallic material, intended to go into direct contact with said belt (20) without the interposition of a coating rubber to cover this cylindrical lateral surface. 27. Apparatus according to any one of the preceding claims, comprising means for wetting with an aqueous solution, preferably only with water, said one or more interposition bands (61, 62; 63).